Michael Romero, a fitness instructor at Gertz Ressler Charter High School in Los Angeles, pumps a 30-pound ammunition can during a timed physical training exercise at the Marine Corps Recruit Depot in San Diego.

Michael Romero, a fitness instructor at Gertz Ressler Charter High School in Los Angeles, pumps a 30-pound ammunition can during a timed physical training exercise at the Marine Corps Recruit Depot in San Diego. (Don Bartletti / Los Angeles Times)